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    <title>练习</title>
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            <span class="one">第一课</span>
            <span>第二课</span>
            <span>第三课</span>
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            <ul>
                <li>01</li>
                <li>02</li>
                <li>03</li>
                <li>04</li>
                <li>05</li>
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        <div class="three">
            <ul>
                <li>001</li>
                <li>002</li>
                <li>003</li>
                <li>004</li>
                <li>005</li>
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        <div class="three">
            <ul>
                <li>0001</li>
                <li>0002</li>
                <li>0003</li>
                <li>0004</li>
                <li>0005</li>
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